At the top of this page, it should state that most videos have to be placed in Timelines. The exception is videos used as menu backgrounds.
I think there is some confusion when it comes to videos that precede the opening menu, such as the FBI warning, animated logos, video intros. Even though they are not accessed via a menu button, they need to be in Timelines.
I agree it can be is an area of confusion, but the third sentence in the first section, says: